This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Anellis, A Articles by Ross, E W Search for Related Content PubMed PubMed Citation Articles by Anellis, A Articles by Ross, E W, Jr Agricola Articles by Anellis, A Articles by Ross, E W

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1977 December; 34(6): 823-831

Cryogenic gamma irradiation of prototype pork and chicken and antagonistic effect between Clostridium botulinum types A and B.

ABSTRACT

Inoculated, irradiated pork (2,300 cans) and chicken (2,000 cans) pack studies were performed to establish the 12D dose for these foods. Each can was inoculated with a mixture of 10(6) spores of each of 10 strains of Clostridium botulinum (five type A and five type B), or a total of 10(7) spores. The cans received a series of increasing doses of gamma rays (60Co) at -30 +/- 10 degrees C; they were incubated for 6 months at 30 +/- 2 degrees C and examined for swelling, toxicity, and recoverable botulinal cells. The highest rate of swelling for both foods occurred within the first week of incubation, and maximum swelling was observed within 4 to 5 weeks. The minimal experimental sterilizing dose (ESD) based on flat, nontoxic sterile cans was 3.0 less than ESD less than or equal to 3.2 Mrad for pork and 4.0 less than ESD less than or equal to 4.2 Mrad for chicken. An analysis of the partial spoilage data by extreme-value statistics indicated with 90% confidence that the rate of spore death in the two foods was not a normal distribution, but appeared to favor a shifted exponential function. Based on the latter distribution, and assuming one most resistant strain in the mixture of 10 used, the 12D dose computed to 4.37 Mrad, with a shoulder of 0.11 Mrad, for pork and to 4.27 Mrad, with a shoulder of 0.51 Mrad, for chicken. An assumption that there were two or more most resistant strains in the inoculum progressively lowered the 12D dose. There was an apparent antagonism between the irradiated type A and B viable strains in the two foods. Cans with type B cells and toxin predominated over cans with type A cells and toxin, but cans with a mixture of type A and B toxins predominated over cans with a mixture of Type A and B cells. At the highest sublethal doses, only type A cells survived in pork, but in chicken there was a least one type B strain that was at least as resistant as type A strains.